Ion pair formation and distribution in organic materials at low temperature due to radiation-induced isothermal luminescence

Organic materials used in the fusion-reactor superconductive magnet are subjected to various radiation at low temperature so that variety of ion species are accumulated. These ion species may lead to part discharge. And then, when the temperature returns to normal temperature, these ion species cause deterioration of the material by reaction. In analysis of the isothermal decay curve of long-lived lumines cence observed in organic materials irradiated at low temperature, the ionization process during the irradiation, the distance distribution of ion pairs occurring upon termination of the irradiation, etc., were studied both theoretically and experimentally. The organic materials tested are PET, PEA, etc. And the radiations used are γ-rays from cobalt-60 and x-rays from an x-ray generator. (Mori, K.)